454 On definite Proportions. 
of ammonium and oxygen, it consists of 15°88 parts of 
ammonium with 84°12 of oxygen in 100. In the quan- 
tity of protoxide of lead, which we have obtained in these 
experiments, there are from’5*70 to 5°72 parts of oxygen, 
which must be an aliquot part of the oxygen contained in 
the 20 per cent. of acid expelled. If we consider nitrogen 
as the radical of the nitrous acid, this acid cannot contain 
three times as much oxygen as the base. The quantity of 
nitrous acid which contains twice 5°72 parts of oxygen is 
18°13; and 1°87 parts only would remain for the water, which 
is manifestly too little, since in the distillation of this salt 
the greatest part of the acid is obtained in a liquid form. 
In order to ascertain this point, I dried a quantity of the 
subsalt very perfectly, until the acid began to escape, so 
that all water adhering to it mechanically must have been 
expelled: the salt had assumed a darker colour, and, when 
ignited in a retort, gave, as before, liquid acid, leaving 81°3 
per cent. of protoxide. Since now the 18°7 per cent, thus 
expelled was chiefly liquid, as before, it is utterly impossi- 
ble, that the nitrous acid should contain twice as much 
oxygen as the base of thesalt; for in this case nothing 
would be left for the water. If again it only contained an 
equal quantity of oxygen with the base, the salt would con- 
tain only 10°93 parts of water of crystallization, and the 
oxygen of this water would observe no regular proportion 
to that of the base. Consequently the composition of this 
salt will not in any manner agree with the laws which pre- 
vail with respect to the other salts, so far as we take nitro- 
gen for the radical of the nitrous acid, 
If on the other hand we considered the nitrous acid as 
composed of ammonium and oxygen, and assumed that there 
is twice as much oxygen in the acid as in the base that neu- 
tralises it, the quantity of the nitrous acid in this salt would 
amount to 13°57 or 13°6 per cent., and 6°4 to 6°68 would 
remain for the water of crystallization. This water would 
contain 5°64 to 5°88 of oxygen; and we may safely con- 
clude, that the base and the water of crystallization con- 
tain equal quantities of oxygen, and the acid twice as much, 
not reckoning that which belongs to the nitrogen. Hence 
the proportions of the component parts of the subnitrite of 
the protoxide of lead are nearly these: 
Protoxide of lead,,......80°0 
Nitrous. acid... .6% 00. 2213°6 
WALET siacsiny seem nee wet on 
We will now, in order to investigate this supposition 
more accurately, examine the composition of the subsalt 
. . MOTE, 
